Hepatitis A virus infections, immunizations, and demographic determinants in children and adolescents, Germany

Hepatitis A is an infectious disease in the liver which is transmitted orally (through close contact) and through contaminated food/water. It is caused by the inflammation of the liver and some of the symptoms include Nausea and vomiting, Abdominal pain, and fatigue.

Image result for hepatitis a in the liver

In this research study, Scientists analyzed this disease by conducting a nationwide, population-based survey in Germany. They investigated the effects of different demographic factors on the presence of Hepatitis antibodies in vaccinated and infected individuals. Mainly children and teens were chosen for this study because of their frequent involvement in the transmission of this disease. These transmissions helped scientists easily find the root/origin of the disease. Furthermore, in Germany, children weren’t vaccinated against Hepatitis and they were highly susceptible to it because of their poor hygiene. Through this outbreak, Scientists were able to study the disease in depth.

In this study, participants were chosen from 167 different municipalities in Germany and 8-10 children were selected from each age group ranging from ages 3-17. Participants were asked for vaccination records and about their previous experiences with Hepatitis A. Serum samples were taken to test for the presence of anti-HAV (Hepatitis A Virus) antibodies.

Image result for serum sample

The scientists mainly wanted to test for seropositivity of HAV antibodies from past immunizations, so they focused on the participants that provided serum samples as well as vaccination records. Then, their samples were tested through quantification and the results were analyzed and split into 3 groups: Current or past HAV infection (Cases with a history of current or past infections), Hepatitis A vaccination (Patients who were vaccinated with Hepatitis A vaccine), and Overall-HAV seropositivity. Furthermore, their analysis looked at the influence of age, gender, place of residence, population size of the community of residence, socioeconomic status, and migrant status on the serum samples in relation to the other 3.

There were a total of 28,299 children and adolescents surveyed. 16,325 of them provided vaccination cards and 13,063 of them were tested for seropositivity of HAV antibodies. Scientists were surprised to find that only 1,880 were considered seropositive. They knew that the HAV vaccination inserted HAV-antibodies into blood so they wondered how the children who got vaccinated were deemed seronegative. They soon found out that the seronegative children were vaccinated with only 1 shot of Hepatits A vaccine whereas the children who were considered seropositive(after vaccination) had gotten Hepatitis A and Recombinant Hepatitis B monovalent vaccines. Figure 1

Additionally, the results showed how increasing age correlated with a higher prevalence of these antibodies, so a 13 year-old was more immune to HAV than a 5 year-old.

Figure 2

Also, children who had migrated from developing countries had more antibodies compared to citizens who were born and brought up in Germany.

In conclusion, from this study, Scientists were able to figure out ways to increase immunity towards Hepatitis A in children. They realized that multiple vaccines were needed for optimal immunity. They also found that as children age, they develop more antibodies and become more immune. The results of this survey/experiment helped the citizens of Germany and other countries understand the ways of preventing  Hepatitis A from becoming a huge epidemic among their children.




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